A known electrophotographic image forming apparatus includes a body casing and a top cover. The body casing has an upwardly open opening. The top cover is disposed at an upper end of the body casing and is configured to expose and cover the opening. In such an image forming apparatus, the opening is exposed by opening of the top cover and maintenance, e.g., cartridge replacement or removal of a jammed sheet, is performed through the exposed opening. Therefore, it is desired that an unexpected closing of the top cover during maintenance is avoided.
In order to avoid the unexpected closing of the top cover, for example, some known printer includes a retaining mechanism that is configured to retain the top cover at an exposing position where the opening is exposed.
In such a printer, a retaining member of the retaining mechanism is urged upward by a spring member to contact a contactable portion of the top cover from below, thereby retaining the top cover at the exposing position.